Immobilizer –DTC Troubleshooting Data Version: 1.2 Date:03-June-2014 Prepared Author: Sarang K/Mithipati P Review & approved by: R A Rode (ERC-E&E) Page: 20 of 67 Copyright © TATA MOTORS Ltd. This document must not be used in any way, such as copying and redistributing to third parties, without the consent of author. B1639-31: Vehicle immobilizer control module no signal Overview: ISO Code B1639-31 DTC simple Description EMS is not transmitting CAN message Customer Symptom Vehicle cannot be started. Fault Effects (On Vehicle) Vehicle cannot be started. Lamp Status (If Any) Immo status lamp On Fault Detection Condition At ignition On Normal Operating Condition Authentication between EMS & Immo is successful Probable Trouble Area W/h, EMS ECU, Immobilizer Healing Condition Component Details: Immobilizer system is designed to prevent vehicle theft by electronically disabling the engine starting system. The engine can be started only with vehicle’s original immobilizer ignition key, which has an electronic identification programmed code. Immobilizer unit is an add-on part on the ignition switch, fitted on the steering column. The engine can be started only with the vehicle’s original immobilizer ignition key. The electronic key communicates the identification code to ICU when the key is turned to the "Ignition ON" position. Preliminary Checks: 1. Check the CAN H & CANL wires between EMS & Immobilizer. 2. EMS ECU supply & Gnd wires. Trouble Shooting:- Step Checks IF YES IF NO 1. Check the EMS ECU is connector connected to ECU Go to step 1 Connect EMS ECU 2. Check the EMS ECU supply & Gnd wires are properly connected Go to step 2 Correct the connection 3 Check the CAN H & CAN L wires continuity between EMS ECU pin (CAN H 64, CAN L 40) & Immobilizer pin (CANH 3, CAN L 8) Go to step 3 Correct the connection 4 Check the resistance between CAN H & CAN L at immo pin 3 & 8, it should be 60±5Ω Go to step 4 Check any short circuit in w/h. 5 Replace the EMS ECU with new good one & pair the ECU with immobilizer. 6 If fault still present in immobilizer replace the immobilizer DTC’s confirmation:- Before handover to customer, ensure that vehicle will start without any error Circuit Schematic Diagram: Please refer the immobilizer circuit schematic VICM pin no Pin description 1 Vbatt (KL30) 2 GND 3 CAN_H(High-speed) 4 Ignition (KL15)
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